I visited this stall in blogcamp. They have interesting cool features. They have developed a collaborative office tools, writer, spreadsheet, presentation, crm tool, etc. The good thing is many contributors can access single document and modify them provided they have access control.

The sad part is they do not use a version control system in back-end! Each change is stored in seperate file and they show the difference based on time of change. It lacks many features which any collaborative tool offers, but it's a beginning.